JP4487131B2

JP4487131B2 - Tire warning device

Info

Publication number: JP4487131B2
Application number: JP2005505417A
Authority: JP
Inventors: 雅俊桑島
Original assignee: Yokohama Rubber Co Ltd
Current assignee: Yokohama Rubber Co Ltd
Priority date: 2003-04-15
Filing date: 2004-04-14
Publication date: 2010-06-23
Anticipated expiration: 2024-04-14
Also published as: EP1619052A4; CN101574913A; EP1619052A1; EP2535210B1; KR20050113280A; EP1619052B1; US20060208863A1; CN101574912A; JPWO2004091943A1; CN101574912B; KR101095290B1; US7391307B2; CN1774350A; WO2004091943A1; CN101574913B; CN100567037C; EP2535210A1

Description

本発明は、ランフラット走行時に空気入りタイヤのランフラット走行限界を警告するタイヤ警報装置に関し、更に詳しくは、ランフラット走行限界を精度良く警告することができるタイヤ警報装置に関する。 The present invention relates to a tire warning device that warns of a run-flat running limit of a pneumatic tire during run-flat running, and more particularly to a tire warning device that can warn of a run-flat running limit with high accuracy.

車両の走行中に空気入りタイヤがパンクした場合でも、数百ｋｍ程度の緊急走行（ランフラット走行）を可能にする技術が市場の要請から多数提案されており、近年、そのような技術を実用化した安全タイヤやタイヤ／ホイール組立体が徐々に普及しつつある。これらの安全タイヤやタイヤ／ホイール組立体は、パンクなどによりタイヤの内圧が減少しても、見た目にタイヤ内圧の低下がわかり難いため、安全性確保の理由により、タイヤの状態を監視する装置を併用することが求められている。
従来、タイヤの状態を監視する装置として、例えば、日本特開平６−２１１０１２号公報に、タイヤの空気圧を検出する空気圧検出手段、タイヤの温度を検出する温度検出手段、空気圧検出手段により検出された空気圧及び温度検出手段により検出されたタイヤ温度に基づいてタイヤのバースト発生を予測するバースト発生予測手段とを備えたタイヤの状態監視装置が開示されている。また、日本特開２０００−３５５２０３号公報に、タイヤ内の空気圧を圧力センサーにより検出して車体側に無線で報知するタイヤ空気圧警報装置が提案されている。
しかしながら、上述した装置は、車両に装着した通常の空気入りタイヤの状態を監視する装置としては好適に使用することができるが、上記安全タイヤやタイヤ／ホイール組立体に用いた場合には、ランフラット走行時にドライバーにランフラット走行限界（タイヤが破壊する前に走行を停止する限界）を精度良く警告することができない。Many technologies that enable emergency travel (run-flat travel) of several hundred km even when pneumatic tires are punctured while the vehicle is running have been proposed due to market demands. Safety tires and tire / wheel assemblies are becoming increasingly popular. These safety tires and tire / wheel assemblies are difficult to see even if the tire internal pressure decreases due to puncture, etc., so a device that monitors the tire condition is used for safety reasons. It is required to be used in combination.
Conventionally, as a device for monitoring the state of a tire, for example, in Japanese Patent Application Laid-Open No. 6-211012, an air pressure detecting means for detecting tire air pressure, a temperature detecting means for detecting tire temperature, and an air pressure detecting means have been detected. A tire condition monitoring device is disclosed that includes burst generation prediction means for predicting tire burst generation based on tire temperature detected by air pressure and temperature detection means. Japanese Laid-Open Patent Publication No. 2000-355203 proposes a tire air pressure alarm device that detects the air pressure in a tire with a pressure sensor and notifies the vehicle body side by radio.
However, the above-described device can be suitably used as a device for monitoring the state of a normal pneumatic tire mounted on a vehicle. However, when used in the above safety tire or tire / wheel assembly, It is not possible to warn the driver of the run-flat driving limit (the limit of stopping the driving before the tire breaks) with high accuracy during flat driving.

本発明の目的は、ランフラット走行時にドライバーにランフラット走行限界を精度良く警告することが可能なタイヤ警報装置を提供することにある。
上記目的を達成する本発明のタイヤ警報装置は、サイドウォール部にランフラット走行を可能にする補強層を配置した空気入りタイヤのランフラット走行限界をランフラット走行時に警告するタイヤ警報装置であって、ランフラット走行限界を警告するのに使用され、前記補強層に対面するサイドウォール部の内面に配置されるタイヤ温度センサーを備えたことを特徴とする。
ランフラット走行を可能にする補強層をサイドウォール部に配置した空気入りタイヤでは、ランフラット走行時に荷重を支持する補強層が発熱して破壊され、ランフラット走行を不能にするが、このようにタイヤ温度センサーを補強層の近傍となるサイドウォール部の内面に配置したので、ランフラット走行の限界を左右する補強層の発熱する温度をタイヤ温度センサーでより正確に測定できるようになり、その温度データを用いてランフラット走行限界を警告することが可能になるため、ランフラット走行時にドライバーにランフラット走行限界を精度良く警告することができる。
本発明の他のタイヤ警報装置は、ランフラット走行時にホイールのリムに取り付けたランフラット用支持体により支持される空気入りタイヤのランフラット走行限界を警告するタイヤ警報装置であって、ランフラット走行限界を警告するのに使用され、前記ランフラット用支持体が前記空気入りタイヤと接触して支持する支持領域に配置されるタイヤ温度センサーを備えたことを特徴とする。
ランフラット用支持体を用いた場合、ランフラット走行時にランフラット用支持体と繰り返し接触する空気入りタイヤのトレッド部が発熱して破壊され、ランフラット走行不能になるが、このようにタイヤ温度センサーをトレッド部の近傍となるランフラット用支持体の支持領域に配置することで、ランフラット走行時に発熱するトレッド部の温度をタイヤ温度センサーでより正確に測定できるようになるため、ランフラット走行時にドライバーにランフラット走行限界を精度良く警告することが可能になる。
本発明の更に他のタイヤ警報装置は、ランフラット走行時にホイールのリムに取り付けたランフラット用支持体の金属製支持部材により支持される空気入りタイヤのランフラット走行限界を警告するタイヤ警報装置であって、ランフラット走行限界を警告するのに使用され、前記金属製支持部材に配置されるタイヤ温度センサーを備えたことを特徴とする。
このように金属製支持部材を備えたランフラット用支持体の場合、熱伝導が良好な金属製支持部材にタイヤ温度センサーを配置することで、発熱するトレッド部の温度をタイヤ温度センサーでより正確に測定できるため、ランフラット走行時にドライバーにランフラット走行限界を精度良く警告することができる。An object of the present invention is to provide a tire warning device that can warn a driver of a run-flat running limit with high accuracy during run-flat running.
The tire alarm device of the present invention that achieves the above object is a tire alarm device that warns a run-flat running limit of a pneumatic tire in which a reinforcement layer that enables run-flat running is arranged on a sidewall portion during run-flat running. The tire temperature sensor is used to warn of a run-flat running limit and is disposed on the inner surface of the sidewall portion facing the reinforcing layer.
In a pneumatic tire with a reinforcement layer on the side wall that enables run-flat running, the reinforcement layer that supports the load during run-flat running is overheated and destroyed, making run-flat running impossible. Since the tire temperature sensor is arranged on the inner surface of the side wall near the reinforcing layer, the temperature generated by the reinforcing layer that determines the limit of run-flat driving can be measured more accurately with the tire temperature sensor. Since it becomes possible to warn the run-flat travel limit using the data, it is possible to warn the driver of the run-flat travel limit with high accuracy during the run-flat travel.
Another tire warning device according to the present invention is a tire warning device that warns of a run-flat running limit of a pneumatic tire supported by a run-flat support attached to a rim of a wheel during run-flat running. It is used to warn of a limit, and is characterized in that it includes a tire temperature sensor disposed in a support area where the run-flat support is supported in contact with the pneumatic tire.
When a run-flat support is used, the tread part of the pneumatic tire that repeatedly contacts the run-flat support during run-flat running is overheated and destroyed, making run-flat running impossible. Is placed in the support area of the run-flat support in the vicinity of the tread part, so that the temperature of the tread part that generates heat during run-flat running can be measured more accurately with the tire temperature sensor. It is possible to warn the driver of the run-flat driving limit with high accuracy.
Still another tire warning device of the present invention is a tire warning device that warns of a run flat running limit of a pneumatic tire supported by a metal support member of a run flat support attached to a wheel rim during run flat running. The tire temperature sensor is used to warn of a run-flat running limit and is disposed on the metal support member.
In the case of a run-flat support body having a metal support member as described above, the tire temperature sensor is arranged on a metal support member with good heat conduction, so that the temperature of the tread portion that generates heat can be more accurately detected by the tire temperature sensor. Therefore, it is possible to warn the driver of the run-flat running limit with high accuracy during run-flat running.

図１は、本発明のタイヤ警報装置のタイヤ側ユニットを補強層に対面するサイドウォール部の内面に取り付けた状態を示す要部断面図である。
図２は、本発明のタイヤ警報装置の一実施形態を示す説明図である。
図３は、近似関数ｆ_０の一例を示すグラフ図である。
図４は、本発明のタイヤ警報装置のタイヤ側ユニットをランフラット用支持体に取り付けた例を示す要部断面図である。
図５（ａ），（ｂ）は、それぞれタイヤ側ユニットを図４のランフラット用支持体に取り付ける他の例を示す断面図である。
図６（ａ），（ｂ）は、それぞれタイヤ側ユニットを図４のランフラット用支持体に取り付ける更に他の例を示す要部拡大断面図である。
図７は、タイヤ側ユニットをランフラット用支持体の金属製支持部材に取り付けた例を示す要部断面図である。
図８は、本発明のタイヤ警報装置の他の実施形態を示す説明図である。
図９は、タイヤ内圧に応じて危険度を評価する評価関数ｆ_１を示すグラフ図である。
図１０は、車両走行速度に応じて危険度を評価する評価関数ｆ_２を示すグラフ図である。
図１１は、タイヤ温度に応じて危険度を評価する評価関数ｆ_３を示すグラフ図である。
図１２は、総合評価関数ｆ_４の一例を示すグラフ図である。FIG. 1 is a cross-sectional view of a main part showing a state in which a tire side unit of a tire alarm device of the present invention is attached to an inner surface of a sidewall portion facing a reinforcing layer.
FIG. 2 is an explanatory view showing an embodiment of the tire warning device of the present invention.
Figure 3 is a graph showing an example of the approximation function f _0.
FIG. 4 is a cross-sectional view of the main part showing an example in which the tire-side unit of the tire alarm device of the present invention is attached to a run-flat support.
FIGS. 5A and 5B are cross-sectional views showing other examples in which the tire-side unit is attached to the run-flat support in FIG.
6 (a) and 6 (b) are enlarged cross-sectional views of main parts showing still other examples in which the tire side unit is attached to the run-flat support body of FIG.
FIG. 7 is a cross-sectional view of the main part showing an example in which the tire-side unit is attached to a metal support member of a run-flat support body.
FIG. 8 is an explanatory view showing another embodiment of the tire warning device of the present invention.
FIG. 9 is a graph showing an evaluation function f ₁ for evaluating the degree of risk according to the tire internal pressure.
Figure 10 is a graph showing an evaluation function f ₂ for evaluating the degree of risk according to the vehicle running speed.
Figure 11 is a graph showing an evaluation function f ₃ for evaluating the degree of risk according to the tire temperature.
Figure 12 is a graph showing an example of a total evaluation function f _4.

以下、本発明の実施の形態について、添付の図面を参照しながら、詳細に説明する。
図１，２において、１はランフラット走行を可能にした空気入りタイヤ、２は空気入りタイヤ１をホイールＷのリムＲに組み付けたタイヤ／ホイール組立体Ｘ内に配置するタイヤ側ユニット、３は車両に装着する車両側ユニットである。
空気入りタイヤ１は、タイヤ内側にインナーライナー層４が配置され、その外側に左右のビード部５間に延設されたカーカス層６が設けられている。カーカス層６の両端部がビード部５に埋設されたビードコア７の周りにビードフィラー８を挟み込むようにしてタイヤ内側から外側に折り返されている。
トレッド部９のカーカス層６外周側にはベルト層１０が配設され、その外周側にベルトカバー層１１が設けられている。両サイドウォール部１２には、インナーライナー層４とカーカス層６との間にランフラット走行を可能にするゴムからなる断面三日月状の補強層１３がそれぞれ配置され、ランフラット走行時にこの補強層１３で荷重を支持することによりランフラット走行できるようにしている。
タイヤ側ユニット２は、タイヤの温度を検出するタイヤ温度センサー１４と空気入りタイヤ１の空洞部内の圧力を検出するタイヤ内圧センサー６０、及びセンサー１４，６０で検出された検出信号を車両側ユニット３に送信する送信手段１５を備えている。送信手段１５は、送信機１５Ａとアンテナ１５Ｂを有し、アンテナ１５Ｂから所定の時間間隔で断続的に検出信号を車両側ユニット３に送信するようになっている。
タイヤ側ユニット２は、補強層１３に対面するサイドウォール部１２の内面領域１２ａに装着され、タイヤ温度センサー１４をランフラット走行の限界を左右する補強層１３の近傍に配置するようにしている。
車両側ユニット３は、アンテナ１５Ｂから送信された検出信号を受信するアンテナ１７Ａと受信機１７Ｂとからなる受信手段１７、検出した温度信号に基づいてランフラット走行限界領域に達したか否かを判定する処理手段１９、処理手段１９でランフラット走行限界領域に達したと判定した際にそれをドライバーに報知する警告手段２０を備えている。
処理手段１９に接続された記憶部２１には、ランフラット走行限界領域に対応する、予め設定した限界温度データが記憶してあり、処理手段１９ではタイヤ温度センサー１４で検出された信号の温度データの値と記憶部２１の限界温度データの値とを比較し、検出信号の温度データの値が限界温度データの値を超えると、ランフラット走行限界領域に達したと判定し、警告手段２０に作動信号を出力する。警告手段２０は、その入力を受けると、ドライバーにランフラット走行限界であることを音や光などにより警告するようになっている。処理手段１９には、時間情報データを供給するクロック手段２２が接続され、処理手段１９から記憶部２１に逐次入力された温度データが、温度の時刻歴データとして記憶部２１に蓄積されるようになっている。
また、処理手段１９では、タイヤ内圧センサー６０で検出した圧力値が予め記憶部２１に記憶した所定の閾値を下回るか否か判定し、検出した圧力値が所定の閾値未満であると、ランフラット走行状態にあると判定する。そして、この判定に基づいて、上述した温度データに基づいてランフラット走行限界領域に達したか否かを判定する。
更に、処理手段１９では、タイヤ温度センサー１４で検出された温度信号のデータ値が上記限界温度のデータ値を超えていない場合、記憶部２１に蓄積された温度の時刻歴データにおいて、最新の温度データから少なくとも３点前までの温度データを用いて、温度の時刻歴データの区分近似関数ｆ_０を求める（図３参照）。近似関数ｆ_０に使用される関数は、具体的には２次以上の多項式、例えば、ｆ_０＝ａｔ^２＋ｂｔ＋ｃやｆ_０＝ａｔ^ｍ＋ｃなどを好ましく用いることができる。但し、ａ，ｂ，ｃ，ｍは係数、ｔは時間（秒）であり、各係数はその関数形に従って最小二乗法等により求めることができる。ここで、温度変化に上昇する傾向もしくは横ばいの傾向がみられる場合、即ち上記関数形を用いた場合において、ａ≧０であるような場合は、現時点でランフラット走行限界に達していなくても、時間を経るとランフラット走行限界に達する可能性が高いため、近似関数ｆ_０を用いて外挿法により最新の温度データ以降の温度の値を時系列的に予想する。予測した温度の値が限界温度データの値に達するまでの時間を算出し、その算出した時間が処理手段１９に接続された表示手段２３に表示され、ランフラット走行限界領域に達するまでの時間を推定してドライバーに知らせる。温度変化に降下する傾向がみられる場合、即ち上記関数形を用いた場合において、ａ＜０であるような場合は、ランフラット走行限界に達するまでの時間を推定しない。
記憶部２１に記憶させる限界温度データの値は、タイヤサイズや構造により適宜選択されるが、一般に５０〜１５０℃の範囲から選択することができる。また、最新の温度データから少なくとも３点前までの温度データとしたのは、急激な温度変化をより正確に捉えるためである。好ましくは、最新の温度データから５点前位までの温度データを用いるようにするのがよい。
上述した空気入りタイヤ１では、ランフラット走行時に荷重を支持する補強層１３が破壊されると、ランフラット走行が不能になるが、その破壊に至る過程において、繰り返し大きく変形する補強層１３の発熱が極めて大きく、他の部分より温度が大幅に上昇する。その温度が高いほどランフラット走行限界となる危険度が高くなる。
本発明では、その知見に基づき、タイヤ温度センサー１４を有するタイヤ側ユニット２を補強層１３近傍のサイドウォール部１２の内面領域１２ａに配置し、タイヤの温度として補強層１３の発熱温度をタイヤ温度センサー１４により正確に測定できるようにし、その温度データを用いて処理手段１９でランフラット走行限界を判定することができるようにしたので、ランフラット走行時にドライバーにランフラット走行限界を精度良く警告することが可能になる。
また、タイヤ温度センサー１４で検出された温度信号のデータ値が限界温度のデータ値を超えていない場合には、ランフラット走行限界領域に達するまでの時間を予測することができるので、ドライバーに予めランフラット走行限界を知らせ、タイヤ交換時期の情報を提供することができる。
図４は、上述した本発明のタイヤ警報装置を、ランフラット走行時に空気入りタイヤ３１を支持するランフラット用支持体３２をホイールＷのリムＲに取り付けたタイヤ／ホイール組立体Ｘ’に使用したものである。空気入りタイヤ３１は、上述した補強層１３がない一般的な構造のものである。
ランフラット用支持体３２は、金属、樹脂などの剛性材から形成された環状シェル３３と、ゴム、弾性樹脂などの弾性材から形成された左右の弾性リング３４とから構成されている。タイヤ／ホイール組立体Ｘ’が車両に装着されて走行中に空気入りタイヤ３１がパンクすると、そのパンクして潰れた空気入りタイヤ３１のトレッド部３１ａが環状シェル３３の外周側の支持領域３３Ｘで支持された状態になり、ランフラット走行を可能にしている。
上記のようなタイヤ／ホイール組立体Ｘ’では、ランフラット走行時に環状シェル３３と繰り返し接触するトレッド部３１ａが発熱して破壊され、ランフラット走行が不能になる。そこで、タイヤ側ユニット２を、トレッド部３１ａと接触して支持する環状シェル３３の支持領域３３Ｘに配置するようにしたのである。図示する例では、環状シェル３３の支持領域３３Ｘがシェル幅方向に並べた２つの凸状支持部３３Ａを凹状接続部３３Ｂで接続して構成されており、その凹状接続部３３Ｂの内面にタイヤ側ユニット２を取り付けている。
タイヤ側ユニット２は、図５（ａ）に示すように、凹状接続部３３Ｂの外面に装着してもよく、また、図５（ｂ）に示すように、凸状支持部３３Ａの内面に配置するようにしてもよい。
タイヤ側ユニット２は、更に、図６（ａ）に示すように、環状シェル３３の外面に形成した凹部３５内にタイヤ側ユニット２を配置してもよく、また、図６（ｂ）に示すように、環状シェル３３の内面に形成した凹部３５内にタイヤ側ユニット２を配置するようにしてもよい。このように凹部３５内にタイヤ側ユニット２を収容することで、タイヤ側ユニット２を支持領域３３Ｘの凸状支持部３３Ａの凸端部外面に取り付け、ランフラット走行時に発熱するトレッド部３１ａに極力近づけた位置に配置することが可能になる。
また、環状シェル３３が金属製支持部材から構成される場合には、熱伝導が極めて良好なため、タイヤ側ユニット２を破損しない箇所であれば環状シェル３３のいずれの位置に、例えば、図７に示すように支持領域３３Ｘから外れた弾性リング３４近傍の環状シェル３３の表面に配置してもよい。
このようにランフラット走行時に空気入りタイヤ３１を支持するランフラット用支持体３２をリムＲに取り付けたタイヤ／ホイール組立体Ｘ’にも本発明のタイヤ警報装置を好適に使用することができる。
また、ランフラット用支持体３２は、上述した構造のものに限定されず、例えば、リムＲに取り付けたＴ字状やＩ字状の中子などからなるランフラット用支持体であってもよい。
図８は、本発明のタイヤ警報装置の他の実施形態を示し、４２はタイヤ／ホイール組立体Ｘ，Ｘ’内に配置するタイヤ側ユニット、４３は車両に装着する車両側ユニットである。
上記と同様の位置に取り付けられるタイヤ側ユニット４２は、タイヤ温度を検出するタイヤ温度センサー４４と、空気入りタイヤの空洞部内の圧力を検出するタイヤ内圧センサー４５、及びタイヤ温度センサー４４とタイヤ内圧センサー４５で検出された信号を車両側ユニット４３に送信する送信手段４６を備えている。送信手段４６は、送信機４６Ａとアンテナ４６Ｂを有し、アンテナ４６Ｂから所定の時間間隔で断続的に検出信号を車両側ユニット４３に送信するようになっている。
車両側ユニット４３は、アンテナ４６Ａから送信された検出信号を受信するアンテナ４８Ａと受信機４８Ｂを有する受信手段４８、車両から車両走行速度を取得する速度取得手段５０、受信手段４８から入力されるタイヤ温度の検出信号とタイヤ内圧の検出信号、及び速度取得手段５０からの検出信号に基づいてランフラット走行限界領域に達したか否かを判定する処理手段５１、処理手段５１でランフラット走行限界領域に達したと判定した際にそれをドライバーに報知する警告手段５２、時間情報データを処理手段５１に供給するクロック手段５３、及び記憶部５４を備えている。
処理手段５１に接続された記憶部５４には処理手段５１から出力された圧力、速度、温度のデータが、時刻歴データとして蓄積されるようになっている。
また、記憶部５４には、タイヤ内圧に応じて危険度を評価する評価関数ｆ_１、車両走行速度に応じて危険度を評価する評価関数ｆ_２、及びタイヤ温度に応じて危険度を評価する評価関数ｆ_３が記憶されている。これらの評価関数は実験から求められるものであり、各評価関数の一例を図９，１０，１１に示す。
図９はタイヤ内圧に応じて危険度を評価する評価関数ｆ_１であり、この評価関数ｆ_１は内圧の増加と共に単調に減少する形で記述され、
ｆ_１＝ａ_１×ｅ^{−Ｃ１ｘＰ}
で表される。式中、ａ_１は正の実数値からなる定数で１０^−１〜１０^１の範囲、Ｃ１は定数で２．０〜８．０の範囲を好ましく使用することができる。Ｐは実際のタイヤ空気圧（ｋＰａ）／タイヤ設定空気圧（ｋＰａ）の比、ｅは自然対数である。定数ａ_１，Ｃ１は、タイヤサイズや構造等によって決まる値である。実際のタイヤ空気圧は、タイヤ内圧センサー４５で検出された値が使用される。なお、図９のグラフ図における横軸は実際のタイヤ空気圧／タイヤ設定空気圧の比Ｐ、縦軸は危険度である。
図１０は車両走行速度に応じて危険度を評価する評価関数ｆ_２であり、この評価関数ｆ_２は車両走行速度の増加と共に単調に増加する形で記述され、
ｆ_２＝ａ_２×Ｖ^Ｃ２
で表される。式中、ａ_２は正の実数値からなる定数で１０^−１〜１０^１の範囲、Ｃ２は定数で１．５〜３．５の範囲を好ましく使用することができる。Ｖは車両の走行速度（ｋｍ／ｈ）と基準速度（１００ｋｍ／ｈ）の比（車両の走行速度／１００）である。定数ａ_２，Ｃ２も、タイヤサイズや構造等によって決まる値である。車両の走行速度は、速度取得手段５０で得られた値が用いられる。なお、図１０のグラフ図における横軸は上記Ｖ、縦軸は危険度である。
図１１はタイヤ温度に応じて危険度を評価する評価関数ｆ_３であり、この評価関数ｆ_３は、温度の増加と共に単調に増加する形で記述され、
ｆ_３＝ａ_３×Ｔ^Ｃ３
で表される。式中、ａ_３は正の実数値からなる定数で４〜２５６の範囲、Ｃ２は定数で１〜４の範囲を好ましく使用することができる。Ｔはタイヤ温度（℃）と基準温度（２５℃）との比（タイヤ温度／２５）である。定数ａ_３，Ｃ３もタイヤサイズや構造等によって決まる値である。タイヤ温度は、タイヤ温度センサー４４で得られた値が用いられる。なお、図１１のグラフ図における横軸は上記Ｔ、縦軸は危険度である。
処理手段５１は、上記評価関数ｆ_１，ｆ_２，ｆ_３を組み合わせて、以下の式で表される式を作成し、これを総合危険度を評価する総合評価関数ｆ_４とする。図１１にその一例をグラフ図にして示す。横軸は時間ｔ、縦軸は総合危険度である。
ｆ_４＝ｍ_１×ａ_１×ｅ^{−Ｃ１ｘＰｔ}＋ｍ_２×ａ_２×Ｖ_ｔ ^Ｃ２
＋ｍ_３×ａ_３×Ｔ_ｔ ^Ｃ３
但し、ｍ_１〜ｍ_３は、重み付けの係数であり、通常はｍ_１〜ｍ_３＝１が用いられるが、タイヤサイズや構造などによって内圧、速度、温度の寄与が異なる場合には、それに応じて適宜変更する。その場合、一般に１〜１０の範囲から選択することができる。また、Ｐ_ｔ、Ｖ_ｔ、Ｔ_ｔは、それぞれ各時刻におけるタイヤ内圧センサー４５、速度取得手段５０、タイヤ温度センサー４４で得られた値である。
次いで、下記式で表すように、総合評価関数ｆ_４において、最新の時刻ｔ_２のデータより一つ前のデータにおける時刻ｔ_１と、それから時間ｔ_０さかのぼった時刻ｔ_１−ｔ_０の区間の時間積分値Ｆ_ｔ＝ｔ１を算出する。時間ｔ_０は、タイヤ側ユニット４２から断続的に得られたデータにおいて、積分する区間のデータ数が５点〜１００点位となる時間の範囲を好ましく用いることができる。例えば、５秒間隔でデータが得られる場合には、２５秒〜５００秒位の範囲とすることができる。時間ｔ_０が小さすぎても大きすぎても正確な判断ができない。特に大きすぎると急激に温度が変化した際に正確な判断ができない恐れがある。

更に、積分値Ｆ_ｔ＝ｔ１からランフラット走行限界の判定に用いる基準値ｆ_ｃを下記式により求める。
ｆ_ｃ＝Ｆ_ｔ＝ｔ１／ｔ_０
次いで、最新の時刻ｔ_２における総合評価関数ｆ_４の値ｆ_ｔ２と基準値ｆ_ｃ、及び記憶部５４に予め記憶させた限界値Ｌを用いて下記の式を満たす場合には、ランフラット限界領域に達していると判定し、警告手段５２がドライバーにランフラット走行限界であることを警告する。
ｆ_ｔ２／ｆ_ｃ＞Ｌ
なお、限界値Ｌは、補強層１３のあるタイヤの場合は、補強層１３の厚さ、物性等、補強層１３のないタイヤで、ランフラット用支持体３２を用いる場合は、ランフラット用支持体３２の環状シェル３３の材質・厚さ・形状等、弾性リング３４の材質・厚さ・形状等により決定されるが、その範囲は２〜５の範囲で適宜設定される。
逐次算出された総合評価関数ｆ_４の値は、処理手段５１から記憶部５４に逐次入力され、時刻歴データとして蓄積される。
また、処理手段５１では、タイヤ内圧センサー４５で検出した圧力値が予め記憶部５４に記憶した所定の閾値を下回るか否か判定し、検出した圧力値が所定の閾値未満であると、ランフラット走行状態にあると判定する。ランフラット走行状態にあると判定した場合に、上述したランフラット走行限界領域に達したか否かを判定する
更に、処理手段５１では、危険度の限界値を超えていないと判断した場合、記憶部５４に蓄積された総合評価関数ｆ_４の値の時刻歴データにおいて、最新のデータから少なくとも３点前までのデータを用いて、総合評価関数ｆ_４の区分近似関数ｆ’_４を求め、次いでその区分近似関数ｆ’_４を用いて外挿法により最新のデータ以降の総合評価関数ｆ_４の値を時系列的に予測する。該近似関数ｆ’_４は、２次以上の多項式、例えば、ｆ’_４＝Ａｘ^２＋Ｂｘ＋Ｃやｆ’_４＝Ａｘ^ｎ＋Ｃなどを好ましく用いることができる。但し、Ａ，Ｂ，Ｃ，ｎは係数、ｘは時間（秒）、各係数はその関数形に従って最小二乗法等により求めることができる。
処理手段５１では、時系列的に予測した値と限界値Ｌを用いて、ランフラット限界領域に達するまでの時間を算出し、その算出した時間が処理手段５１に接続された表示手段５５に表示され、ランフラット走行限界領域に達するまでの時間を推定するようになっている。
本発明者は、ランフラット走行時における限界について鋭意検討し、種々の実験を重ねた結果、以下のことを知見した。
即ち、タイヤ内圧が低いほどランフラット走行限界となる危険度が高く、車両の走行速度が速いほどランフラット走行限界となる危険度が大きくなり、またタイヤ温度が高くなるほどランフラット走行限界となる危険度が増大し、このような危険度を評価する評価関数ｆ_１，ｆ_２，ｆ_３が、上述した非線形に変化する式で表すことができることを見出した。
更に、これらの評価関数ｆ_１，ｆ_２，ｆ_３は、互いに相関関係があり、上述した時間を変数とする総合評価関数ｆ_４として関係付けることができ、その時間積分値Ｆ_ｔ＝ｔ１と予め設定した限界値Ｌとに基づいて、上述したようにランフラット走行限界を判定することで、ランフラット走行時における限界を精度良く判定することができるのである。
上述した総合評価関数ｆ_４は重み付けの係数ｍ_１〜ｍ_３をｆ_１〜ｆ_３にそれぞれ掛け合わせた積の和で規定したが、
ｆ_４＝ａ_１×ｅ^{−Ｃ１ｘＰｔｘｍ１}＋ａ_２×Ｖ_ｔ ^{Ｃ２ｘｍ２}＋ａ_３×Ｔ_ｔ ^{Ｃ３ｘｍ３}
となる総合評価関数ｆ_４であってもよい。但し、限界値Ｌはその式に応じて変更した値となる。
このように本発明の他の実施形態では、相関する評価関数ｆ_１，ｆ_２，ｆ_３より得られる総合評価関数ｆ_４の時間積分値と予め設定した限界値Ｌとに基づいてランフラット走行限界領域に達したか否かを判定することで、ランフラット走行時にドライバーにランフラット走行限界を一層精度よく警告することが可能になる。
また、ランフラット走行限界領域に達するまでの時間を予測することができるので、ドライバーに予めランフラット走行限界を知らせ、タイヤ交換時期の情報を提供することができる。
本発明において、タイヤ側ユニット４２は、タイヤ温度センサー４４を含むユニットと、タイヤ内圧センサー４５を含むユニットとを別々に構成にし、タイヤ温度センサー４４を含むユニットを上記ように高発熱部位の近傍に取り付け、タイヤ内圧センサー４５を含むユニットはリムＲなどに設置するようにしてもよい。
記憶部５４には、新車購入時点、あるいはタイヤ交換時点でのタイヤ内圧を車両の指定空気圧（車両に記載された空気圧、その記載がない場合はＪＡＴＭＡ（２００２年）に記載の空気圧）に設定した後、最大１０００ｋｍ程度まで走行したタイヤ初期時のタイヤ内圧、走行速度、タイヤ温度のデータをそれぞれマップデータとして記憶させ、処理手段５１が、各マップデータの平均値をそれぞれタイヤ内圧、走行速度、タイヤ温度の基準データとして算出し、タイヤ初期以降の走行時に得られるタイヤ内圧、走行速度、タイヤ温度のデータと基準データとの値を比較して、基準データとのずれ量を算出するように構成するのがよい。これにより、タイヤ初期後の通常走行時におけるタイヤの状態を容易に検証することができる。
以上、タイヤ警報装置の好ましい実施形態を説明したが、本発明は、上述した実施形態に限定されず、他の態様であってもよいことはいうまでもなく、添付の請求の範囲によって規定されるものである。Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1 and 2, 1 is a pneumatic tire that enables run-flat running, 2 is a tire-side unit that is disposed in a tire / wheel assembly X in which the pneumatic tire 1 is assembled to a rim R of a wheel W, This is a vehicle-side unit that is mounted on the vehicle.
In the pneumatic tire 1, an inner liner layer 4 is disposed on the inner side of the tire, and a carcass layer 6 extending between the left and right bead portions 5 is provided on the outer side thereof. Both ends of the carcass layer 6 are folded back from the inner side of the tire so as to sandwich the bead filler 8 around the bead core 7 embedded in the bead part 5.
A belt layer 10 is disposed on the outer peripheral side of the carcass layer 6 of the tread portion 9, and a belt cover layer 11 is provided on the outer peripheral side thereof. Both side wall portions 12 are provided with a crescent-shaped reinforcing layer 13 made of rubber that enables run-flat running between the inner liner layer 4 and the carcass layer 6, respectively. By supporting the load, run flat running is enabled.
The tire side unit 2 includes a tire temperature sensor 14 that detects the temperature of the tire, a tire internal pressure sensor 60 that detects the pressure in the cavity of the pneumatic tire 1, and the detection signals detected by the

sensors

14 and 60. The transmission means 15 for transmitting to is provided. The transmission means 15 includes a transmitter 15A and an antenna 15B, and intermittently transmits detection signals from the antenna 15B to the vehicle-side unit 3 at predetermined time intervals.
The tire-side unit 2 is mounted on the inner surface area 12a of the sidewall portion 12 facing the reinforcing layer 13, and the tire temperature sensor 14 is disposed in the vicinity of the reinforcing layer 13 that determines the limit of run-flat travel.
The vehicle side unit 3 determines whether or not the run-flat travel limit region has been reached based on the receiving means 17 comprising the antenna 17A and the receiver 17B for receiving the detection signal transmitted from the antenna 15B and the detected temperature signal. When the processing means 19 determines that the run-flat travel limit area has been reached, the processing means 19 is provided with warning means 20 for notifying the driver of the fact.
The storage unit 21 connected to the processing unit 19 stores preset limit temperature data corresponding to the run-flat travel limit region. The processing unit 19 detects the temperature data of the signal detected by the tire temperature sensor 14. And the value of the limit temperature data in the storage unit 21 are compared, and if the value of the temperature data of the detection signal exceeds the value of the limit temperature data, it is determined that the run flat travel limit region has been reached, and the warning means 20 An operation signal is output. When the warning means 20 receives the input, the warning means 20 warns the driver that it is the run-flat running limit by sound or light. Clock means 22 for supplying time information data is connected to the processing means 19 so that temperature data sequentially input from the processing means 19 to the storage section 21 is accumulated in the storage section 21 as temperature time history data. It has become.
Further, the processing means 19 determines whether or not the pressure value detected by the tire internal pressure sensor 60 is lower than a predetermined threshold value stored in advance in the storage unit 21, and if the detected pressure value is less than the predetermined threshold value, the run flat is determined. It is determined that the vehicle is in a running state. Then, based on this determination, it is determined whether or not the run flat travel limit region has been reached based on the temperature data described above.
Further, in the processing means 19, when the data value of the temperature signal detected by the tire temperature sensor 14 does not exceed the data value of the limit temperature, the latest temperature in the time history data of the temperature accumulated in the storage unit 21. by using the temperature data from the data to at least 3 temae, obtaining a piecewise approximation function f ₀ of the time history data of the temperature (I see FIG. 3). Specifically, as the function used for the approximate function f ₀ , a polynomial having a second or higher order, for example, f ₀ = at ² + bt + c or f ₀ = at ^m + c can be preferably used. However, a, b, c, and m are coefficients, and t is time (seconds). Each coefficient can be obtained by the least square method or the like according to its function form. Here, when the temperature change tends to increase or level, that is, when the above function form is used, if a ≧ 0, the run-flat running limit may not be reached at the present time. Since the possibility of reaching the run-flat running limit is high with time, the temperature values after the latest temperature data are predicted in time series by extrapolation using the approximate function f ₀ . The time until the predicted temperature value reaches the value of the limit temperature data is calculated, the calculated time is displayed on the display means 23 connected to the processing means 19, and the time until the run flat travel limit area is reached is calculated. Estimate and inform the driver. If the temperature change tends to decrease, that is, when the above function form is used, if a <0, the time until the run-flat travel limit is reached is not estimated.
Although the value of the limit temperature data memorize | stored in the memory | storage part 21 is suitably selected according to a tire size or a structure, generally it can select from the range of 50-150 degreeC. Further, the reason why the temperature data from the latest temperature data to at least three points before is used in order to capture a rapid temperature change more accurately. Preferably, temperature data from the latest temperature data up to five points ahead is used.
In the pneumatic tire 1 described above, when the reinforcing layer 13 that supports the load during the run-flat running is broken, the run-flat running becomes impossible, but the heat of the reinforcing layer 13 that repeatedly deforms greatly in the process leading to the breaking. Is extremely large, and the temperature rises significantly over other parts. The higher the temperature, the higher the risk of reaching the run-flat travel limit.
In the present invention, based on the knowledge, the tire side unit 2 having the tire temperature sensor 14 is disposed in the inner surface region 12a of the sidewall portion 12 in the vicinity of the reinforcing layer 13, and the heat generation temperature of the reinforcing layer 13 is set as the tire temperature. Since the sensor 14 can measure accurately and the temperature data can be used to determine the run-flat travel limit by the processing means 19, the driver is warned of the run-flat travel limit with high accuracy during the run-flat travel. It becomes possible.
In addition, when the data value of the temperature signal detected by the tire temperature sensor 14 does not exceed the limit temperature data value, it is possible to predict the time until the run-flat travel limit region is reached. It can inform you of the run-flat driving limit and provide information on when to change tires.
FIG. 4 shows that the tire alarm device of the present invention described above is used for a tire / wheel assembly X ′ in which a run-flat support body 32 that supports a pneumatic tire 31 during run-flat travel is attached to a rim R of a wheel W. Is. The pneumatic tire 31 has a general structure without the reinforcing layer 13 described above.
The run-flat support 32 includes an annular shell 33 formed from a rigid material such as metal or resin, and left and right elastic rings 34 formed from an elastic material such as rubber or elastic resin. When the tire / wheel assembly X ′ is mounted on the vehicle and the pneumatic tire 31 is punctured while traveling, the tread portion 31a of the punctured and collapsed pneumatic tire 31 is supported by the support region 33X on the outer peripheral side of the annular shell 33. It is in a supported state, enabling run-flat travel.
In the tire / wheel assembly X ′ as described above, the tread portion 31a that repeatedly comes into contact with the annular shell 33 during the run-flat running is heated and broken, and the run-flat running becomes impossible. Therefore, the tire side unit 2 is arranged in the support region 33X of the annular shell 33 that supports the tire side unit 2 in contact with the tread portion 31a. In the illustrated example, the support region 33X of the annular shell 33 is configured by connecting two convex support portions 33A arranged in the shell width direction by a concave connection portion 33B, and the inner surface of the concave connection portion 33B is connected to the tire side. Unit 2 is attached.
The tire side unit 2 may be mounted on the outer surface of the concave connection portion 33B as shown in FIG. 5 (a), and arranged on the inner surface of the convex support portion 33A as shown in FIG. 5 (b). You may make it do.
Further, as shown in FIG. 6A, the tire side unit 2 may be disposed in a recess 35 formed on the outer surface of the annular shell 33, as shown in FIG. 6B. As described above, the tire-side unit 2 may be disposed in the recess 35 formed on the inner surface of the annular shell 33. By accommodating the tire-side unit 2 in the recess 35 in this way, the tire-side unit 2 is attached to the outer surface of the convex end portion of the convex support portion 33A of the support region 33X, and as much as possible to the tread portion 31a that generates heat during run-flat travel. It becomes possible to arrange in a close position.
Further, when the annular shell 33 is composed of a metal support member, the heat conduction is extremely good, so any position of the annular shell 33 may be used as long as the tire side unit 2 is not damaged, for example, FIG. As shown in FIG. 3, the elastic shell 34 may be disposed on the surface of the annular shell 33 in the vicinity of the elastic ring 34 deviated from the support region 33X.
Thus, the tire alarm device of the present invention can also be suitably used for the tire / wheel assembly X ′ in which the run-flat support 32 that supports the pneumatic tire 31 during the run-flat travel is attached to the rim R.
The run-flat support 32 is not limited to the structure described above, and may be a run-flat support made of a T-shaped or I-shaped core attached to the rim R, for example. .
FIG. 8 shows another embodiment of the tire warning device according to the present invention, wherein 42 is a tire side unit disposed in the tire / wheel assemblies X and X ′, and 43 is a vehicle side unit mounted on the vehicle.
The tire-side unit 42 mounted at the same position as described above includes a tire temperature sensor 44 that detects the tire temperature, a tire internal pressure sensor 45 that detects the pressure in the cavity of the pneumatic tire, and the tire temperature sensor 44 and the tire internal pressure sensor. The transmission means 46 which transmits the signal detected by 45 to the vehicle side unit 43 is provided. The transmission means 46 includes a transmitter 46A and an antenna 46B, and intermittently transmits detection signals to the vehicle-side unit 43 from the antenna 46B at predetermined time intervals.
The vehicle-side unit 43 includes a receiving means 48 having an antenna 48A and a receiver 48B for receiving a detection signal transmitted from the antenna 46A, a speed obtaining means 50 for obtaining a vehicle traveling speed from the vehicle, and tires inputted from the receiving means 48. Based on the detection signal of the temperature, the detection signal of the tire internal pressure, and the detection signal from the speed acquisition means 50, the processing means 51 for determining whether or not the run flat travel limit area has been reached, and the run means 51 in the run flat travel limit area Is provided with a warning means 52 for notifying the driver of this, a clock means 53 for supplying time information data to the processing means 51, and a storage section 54.
The storage unit 54 connected to the processing unit 51 stores the pressure, speed, and temperature data output from the processing unit 51 as time history data.
The storage unit 54 also evaluates the risk according to the evaluation function f ₁ that evaluates the risk according to the tire internal pressure, the evaluation function f ₂ that evaluates the risk according to the vehicle traveling speed, and the tire temperature. the evaluation function f ₃ is stored. These evaluation functions are obtained from experiments, and an example of each evaluation function is shown in FIGS.
FIG. 9 shows an evaluation function f ₁ for evaluating the degree of risk in accordance with the tire internal pressure, and this evaluation function f ₁ is described in a form that monotonously decreases as the internal pressure increases.
f _₁ = _a ₁ × ^{e -C1xP}
It is represented by In the formula, a ₁ is preferably a constant consisting of a positive real value, and a range of 10 ⁻¹ to 10 ¹ , and C 1 is preferably a constant being in a range of 2.0 to 8.0. P is a ratio of actual tire air pressure (kPa) / tire set air pressure (kPa), and e is a natural logarithm. The constants a ₁ and C1 are values determined by the tire size, structure, and the like. As the actual tire pressure, a value detected by the tire internal pressure sensor 45 is used. In the graph of FIG. 9, the horizontal axis represents the actual tire air pressure / tire set air pressure ratio P, and the vertical axis represents the degree of danger.
FIG. 10 shows an evaluation function f ₂ that evaluates the degree of risk in accordance with the vehicle traveling speed, and this evaluation function f ₂ is described in a monotonically increasing manner as the vehicle traveling speed increases.
f _₂ = _a ₂ × ^{V C2}
It is represented by In the formula, a ₂ is preferably a constant consisting of a positive real value, and a range of 10 ⁻¹ to 10 ¹ , and C 2 is preferably a constant being in a range of 1.5 to 3.5. V is the ratio of the vehicle traveling speed (km / h) to the reference speed (100 km / h) (vehicle traveling speed / 100). The constants a ₂ and C2 are also values determined by the tire size, structure, and the like. The value obtained by the speed acquisition means 50 is used for the traveling speed of the vehicle. In the graph of FIG. 10, the horizontal axis represents the V, and the vertical axis represents the degree of danger.
FIG. 11 shows an evaluation function f ₃ that evaluates the degree of risk according to the tire temperature, and this evaluation function f ₃ is described in a form that increases monotonously with an increase in temperature.
f ₃ = a ₃ × TC ³
It is represented by Wherein, _{a 3} in the range of 4-256 at constant consisting of positive real values, C2 can be used preferably ranges from 1 to 4 constant. T is a ratio (tire temperature / 25) between the tire temperature (° C.) and the reference temperature (25 ° C.). The constants a ₃ and C3 are also values determined by the tire size, structure, and the like. As the tire temperature, a value obtained by the tire temperature sensor 44 is used. In the graph of FIG. 11, the horizontal axis represents T and the vertical axis represents the degree of risk.
The processing means 51 combines the evaluation functions f ₁ , f ₂ , and f ₃ to create an expression represented by the following expression, and uses this as an overall evaluation function f ₄ for evaluating the overall risk. FIG. 11 shows an example of the graph. The horizontal axis is time t, and the vertical axis is the overall risk.
_{_{_{f 4 = m 1 × a 1}}} × e -C1xPt + m 2 × a 2 × V t C2
+ M ₃ × a ₃ × T _t ^C3
However, m _{1 to} m ₃ are weighting coefficients, and usually m _{1 to} m ₃ = 1. However, if the contribution of internal pressure, speed, and temperature differs depending on the tire size and structure, etc. Change accordingly. In that case, it can generally select from the range of 1-10. Further, P _t , V _t , and T _t are values obtained by the tire internal pressure sensor 45, the speed acquisition unit 50, and the tire temperature sensor 44, respectively, at each time.
Then, as represented by the following formula, in synthetic evaluation function f _4, a time t ₁ in the latest time t ₂ the data from the previous data, then the time t ₀ back time t ₁ -t ₀ interval The time integration value F _{t = t1} is calculated. As the time t ₀ , in the data obtained intermittently from the tire-side unit 42, a time range in which the number of data in the integration interval is about 5 to 100 points can be preferably used. For example, when data is obtained at intervals of 5 seconds, it can be in the range of about 25 seconds to 500 seconds. It can not be accurately determined or too large for the time t ₀ is too small. In particular, if it is too large, there is a possibility that an accurate judgment cannot be made when the temperature changes suddenly.

Moreover, obtaining a reference value f _c using the integrated value F _{t = t1} to determine the run-flat running limit by the following equation.
_{_{f c = F t = t1 /}} t 0
Next, when the following equation is satisfied using the value f _t2 of the comprehensive evaluation function f _{4 at} the latest time t ₂ , the reference value f _c , and the limit value L stored in the storage unit 54 in advance, the run-flat limit It is determined that the vehicle has reached the area, and the warning means 52 warns the driver that the vehicle is at the run-flat travel limit.
f _t2 / f _c > L
Note that the limit value L is a tire having the reinforcing layer 13, a tire having no reinforcing layer 13 such as a thickness and physical properties of the reinforcing layer 13, and a run-flat support 32 when the run-flat support 32 is used. Although it is determined by the material, thickness, shape, etc. of the annular shell 33 of the body 32 and the material, thickness, shape, etc. of the elastic ring 34, the range is appropriately set in the range of 2-5.
Sequentially calculated values of the total evaluation function f ₄ is sequentially input from the processing unit 51 in the storage unit 54, it is stored as time history data.
Further, the processing means 51 determines whether or not the pressure value detected by the tire internal pressure sensor 45 is lower than a predetermined threshold value stored in the storage unit 54 in advance, and if the detected pressure value is less than the predetermined threshold value, the run flat is determined. It is determined that the vehicle is in a running state. When it is determined that the vehicle is in the run-flat travel state, it is determined whether or not the above-described run-flat travel limit region has been reached. Further, when the processing means 51 determines that the risk limit value has not been exceeded, in time history data of the accumulated value of the total evaluation function f ₄ in section 54, using data from the most recent data until at least 3 temae obtains a division approximation function f _'4 of the total evaluation function f _4, then Using the piecewise approximation function f ′ ₄ , the value of the comprehensive evaluation function f ₄ after the latest data is predicted in time series by extrapolation. As the approximate function f ′ ₄ , a second or higher order polynomial, for example, f ′ ₄ = Ax ² + Bx + C or f ′ ₄ = Ax ⁿ + C can be preferably used. However, A, B, C, and n are coefficients, x is time (seconds), and each coefficient can be obtained by the least square method or the like according to its function form.
The processing means 51 uses the time-series predicted value and the limit value L to calculate the time until reaching the run-flat limit region, and displays the calculated time on the display means 55 connected to the processing means 51. The time required to reach the run-flat travel limit region is estimated.
The inventor diligently studied the limits at the time of run-flat running, and as a result of repeating various experiments, the inventors have found the following.
That is, the lower the tire internal pressure, the higher the risk of reaching the run-flat travel limit, the higher the vehicle traveling speed, the greater the risk of reaching the run-flat travel limit, and the higher the tire temperature, the risk of reaching the run-flat travel limit. It has been found that the evaluation functions f ₁ , f ₂ , and f ₃ for evaluating the degree of risk can be expressed by the above-described nonlinearly changing formula.
Further, these evaluation functions f ₁ , f ₂ , and f ₃ are correlated with each other, and can be related as a comprehensive evaluation function f ₄ having the above-described time as a variable, and the time integration value F _{t = t 1} and By determining the run-flat travel limit based on the preset limit value L as described above, it is possible to accurately determine the limit during run-flat travel.
Although the synthetic evaluation function _{f 4} described above was defined by the sum of the products obtained by multiplying each coefficient _m 1 ~m ₃ of weighting _f 1 ~f _3,
_{_{^{f 4 = a 1 × e -C1xPtxm1}}} + a 2 × V t C2xm2 + a 3 × T t C3xm3
It may be a comprehensive evaluation function f ₄ to be. However, the limit value L is a value changed according to the equation.
As described above, in another embodiment of the present invention, the run-flat running is performed based on the time integration value of the comprehensive evaluation function f ₄ obtained from the correlated evaluation functions f ₁ , f ₂ , and f ₃ and the preset limit value L. By determining whether or not the limit area has been reached, it is possible to warn the driver of the run-flat running limit with higher accuracy during the run-flat running.
In addition, since the time required to reach the run-flat travel limit region can be predicted, the driver can be informed of the run-flat travel limit in advance, and information on the tire replacement time can be provided.
In the present invention, the tire-side unit 42 includes a unit including the tire temperature sensor 44 and a unit including the tire internal pressure sensor 45 separately, and the unit including the tire temperature sensor 44 is located near the high heat generation portion as described above. The unit including the attachment and tire internal pressure sensor 45 may be installed on the rim R or the like.
In the storage unit 54, the tire internal pressure at the time of new vehicle purchase or tire replacement is set to the specified air pressure of the vehicle (the air pressure described in the vehicle, or the air pressure described in JATMA (2002) if there is no description). Thereafter, the tire internal pressure, traveling speed, and tire temperature data at the initial stage of traveling to a maximum of about 1000 km are stored as map data, and the processing means 51 stores the average values of the map data respectively for the tire internal pressure, the traveling speed, and the tire. It is calculated as temperature reference data, and is configured to calculate the amount of deviation from the reference data by comparing the tire internal pressure, running speed, and tire temperature data obtained during driving after the initial stage of the tire with the reference data. It is good. Thereby, the state of the tire during normal running after the initial tire can be easily verified.
As mentioned above, although preferable embodiment of the tire warning device was described, this invention is not limited to embodiment mentioned above, It cannot be overemphasized that it may be another aspect, and is prescribed | regulated by the attached claim. Is.

上述した優れた効果を有する本発明のタイヤ警報装置は、ランフラット走行時に空気入りタイヤのランフラット走行限界を警告するタイヤ警報装置として、極めて有効に利用することができる。 The tire alarm device of the present invention having the above-described excellent effect can be used very effectively as a tire alarm device that warns the run-flat travel limit of a pneumatic tire during run-flat travel.

Claims

A tire alarm device that warns a run-flat running limit of a pneumatic tire (1) having a reinforcing layer (13) that enables run-flat running on a sidewall (12) during run-flat running ,
Transmitting means and the pneumatic tire and transmits the pre-Symbol tire temperature sensor (14), the tire temperature sensor (14) detects signals disposed on the inner surface of the sidewall portion facing the reinforcing layer (13) (12) A tire side unit (2) provided with a tire internal pressure sensor (60) for detecting the pressure in the cavity of (1);
Receiving means (17) for receiving a signal from the transmitting means, processing means (19) and warning means (20) sequentially connected to the receiving means (17), and preset corresponding to the run flat travel limit region A vehicle-side unit (3) having a storage unit (21) for storing limit temperature data and a predetermined threshold and storing temperature data input through the processing means (19) as temperature time history data. And
The processing means (19) compares the temperature data value of the signal detected by the tire temperature sensor (14) with the value of the limit temperature data,
When the value of the temperature data of the detection signal exceeds the value of the limit temperature data, it is determined that the run flat travel limit region has been reached, and an operation signal is output to the warning means (20).
When the value of the temperature data of the detection signal does not exceed the value of the limit temperature data, it is determined that the run flat travel limit region has not been reached, and the time history data of the temperature accumulated in the storage unit (21). In the above, a piecewise approximate function of time history data of temperature is obtained using temperature data from the latest temperature data to at least three points before, and the temperature values after the latest temperature data are extrapolated using this approximate function. Is calculated in time series, and the time until the predicted temperature value reaches the limit temperature data value is calculated,
And the said processing means (19) determines whether the pressure value detected with the said tire internal pressure sensor (60) is less than a predetermined threshold value, and when the detected pressure value is less than the said predetermined threshold value, A tire warning device that determines that the vehicle is in a run-flat running state and determines whether or not the run-flat running limit region has been reached based on temperature data input through the processing means (19) .

A tire alarm device that warns a run-flat running limit of a pneumatic tire (1) having a reinforcing layer (13) that enables run-flat running on a sidewall (12) during run-flat running,
A tire temperature sensor (44) disposed on the inner surface of the sidewall portion (12) facing the reinforcing layer (13), and a tire internal pressure sensor (45) for detecting the pressure in the hollow portion of the pneumatic tire (1); Detection from the speed acquisition means (50) for acquiring the traveling speed of the vehicle equipped with the pneumatic tire (1), the tire temperature sensor (44), the tire internal pressure sensor (45), and the speed acquisition means (50) Processing means (51) for determining whether or not the run-flat travel limit area has been reached based on the signal, and warning means for issuing a warning when it is determined that the processing means (51) has reached the run-flat travel limit area (52) A tire alarm device.

A tire alarm device that alerts the run runflat limit of run-flat support mounted on a rim R of a wheel W during flat running (32) A pneumatic tire which is supported by (1), for the front Symbol runflat A tire alarm device comprising a tire temperature sensor (14, 44) disposed in a support region (33X) supported by a support in contact with the pneumatic tire (1) .

A tire warning device that warns of a run flat travel limit of a pneumatic tire (1) supported by a metal support member of a run flat support (32) attached to a rim W of a wheel W during run flat travel ,
Tire temperature sensor arranged in front Symbol metallic support member (14), the tire the tire temperature sensor (14) for detecting the pressure in the cavity of the transmitting means and the pneumatic tire and transmits the detected signal (1) A tire side unit (2) provided with an internal pressure sensor (60);
Receiving means (17) for receiving a signal from the transmitting means, processing means (19) and warning means (20) sequentially connected to the receiving means (17), and preset corresponding to the run flat travel limit region A vehicle-side unit (3) having a storage unit (21) for storing limit temperature data and a predetermined threshold and storing temperature data input through the processing means (19) as temperature time history data. And
The processing means (19) compares the temperature data value of the signal detected by the tire temperature sensor (14) with the value of the limit temperature data,
When the value of the temperature data of the detection signal exceeds the value of the limit temperature data, it is determined that the run flat travel limit region has been reached, and an operation signal is output to the warning means (20).
When the value of the temperature data of the detection signal does not exceed the value of the limit temperature data, it is determined that the run flat travel limit region has not been reached, and the time history data of the temperature accumulated in the storage unit (21). In the above, a piecewise approximate function of time history data of temperature is obtained using temperature data from the latest temperature data to at least three points before, and the temperature values after the latest temperature data are extrapolated using this approximate function. Is calculated in time series, and the time until the predicted temperature value reaches the limit temperature data value is calculated,
And the said processing means (19) determines whether the pressure value detected with the said tire internal pressure sensor (60) is less than a predetermined threshold value, and when the detected pressure value is less than the said predetermined threshold value, A tire warning device that determines that the vehicle is in a run-flat running state and determines whether or not the run-flat running limit region has been reached based on temperature data input through the processing means (19) .

A tire warning device for warning a run-flat travel limit of a pneumatic tire (1) supported by a metal support member of a run-flat support (32) attached to a rim R of a wheel W during run-flat travel ,
A tire temperature sensor (44) arranged in front Symbol metallic support member, the tire inner pressure sensor for detecting the pressure in the cavity of the pneumatic tire (1) (45), equipped with the pneumatic tire (1) Based on detection signals from the speed acquisition means (50) for acquiring the traveling speed of the vehicle, the tire temperature sensor (44), the tire internal pressure sensor (45), and the speed acquisition means (50), the run flat travel limit region is reached. A tire warning device comprising: processing means (51) for determining whether or not the vehicle has been hit; and warning means (52) for issuing a warning when it is determined that the processing means (51) has reached the run-flat travel limit region .

Based on the signal detected by the tire temperature sensor (14) , a processing means (19) for determining whether or not the run flat travel limit area has been reached, and the processing means (19) reaches the run flat travel limit area. The tire warning device according to claim 3 , further comprising warning means (20) that issues a warning when it is determined that the warning has been made.

Receiving a tire side unit (2) having a transmitting means for transmitting the detected signal (15) at the tire temperature sensor (14) and the tire temperature sensor (14), the signal from the transmitting means (15) The tire warning device according to claim 6 , comprising a vehicle side unit (3) provided with a receiving means (17), the processing means (19) and the warning means (20) .

The vehicle-side unit (3) comprises a storage unit for storing the limit temperature data set pre Me that corresponds to the run-flat running limit region has a (21), said processing means (19) is the tire temperature sensor (14 ) in comparing the values of the limit temperature data of the temperature data of the detected signal, the value of the temperature data of the detection signal reaches the run-flat running limit range when it exceeds the value of the limit temperature data The tire warning device according to claim 7, which is determined as follows.

Has a tire pressure sensor (60) for detecting the pressure in the cavity of the pneumatic tire (1), wherein the processing means (19), the pressure value detected by the tire inner pressure sensor (60) is a predetermined threshold value determines whether below, determines that the run-flat running state when the detected pressure value is less than the predetermined threshold value, the run-flat on the basis of the temperature data inputted through said processing means (19) The tire warning device according to claim 8 , wherein it is determined whether or not a travel limit region has been reached.

The storage unit (21) accumulates temperature data input through the processing means (19) as temperature time history data , and the processing means (19) determines that the run-flat travel limit area has not been reached. when, in the time history data of the accumulated temperature in the storage unit (21), using the temperature data from the most recent temperature data up to at least 3 temae obtains a division approximation function time history data of the temperature , claim 9 using the approximation function chronologically predict the value of the temperature since the last temperature data by extrapolation, to calculate the time until the value of the predicted temperature reaches the value of the limit temperature data The tire alarm device described in 1.

A tire internal pressure sensor (45) for detecting the pressure in the cavity of the pneumatic tire (1) , a speed acquisition means (50) for acquiring the traveling speed of a vehicle equipped with the pneumatic tire (1) , and the tire A processing means (51) for determining whether or not the run-flat travel limit region has been reached based on detection signals from the temperature sensor (44) , the tire internal pressure sensor (45) and the speed acquisition means (50) ; and the processing means The tire warning device according to claim 3 , further comprising warning means (52) for issuing a warning when it is determined that (51) has reached the run-flat travel limit region.

Said processing means (51) is an evaluation function f ₁ for evaluating the degree of risk in response to the pressure in the cavity of a pneumatic tire (1), an evaluation function f ₂ for evaluating the degree of risk according to the running speed, the synthetic evaluation function f ₄ is calculated by integrating the time integration value at the time as a variable evaluation function f ₃ and a combination of time for evaluating the degree of risk according to the tire temperature, said time integral value and the preset limit values The tire warning device according to claim 5 or 11 , wherein it is determined whether or not the run flat travel limit region has been reached based on L.

A storage unit (54) for storing a preset limit value L is included, and the processing means (51) compares the time integral value with the limit value L, and the time integral value exceeds the limit value L. In the case, the tire warning device according to claim 12 , wherein it is determined that the run flat travel limit region has been reached.

Said storage unit (54) stores a predetermined threshold value, said processing means (51), the pressure the pressure value detected by the tire pressure sensor (45) determines whether less than a predetermined threshold value, detected If the value is less than the predetermined threshold value, it determines that the run-flat running condition, the tire alarm device according to judges claim 13 whether reached run-flat running limit range.

Said storage unit (54) stores the time history data of the values of the comprehensive evaluation function f _4, wherein the processing means (51), when it is determined that not reached the runflat limit region, the storage unit in time history data of the accumulated value of the total evaluation function f ₄ in (54), using data from the latest data to at least 3 temae obtains a division approximation function f _'4 of the total evaluation function f _4, Using the piecewise approximation function f ′ ₄ , the extrapolation method predicts the value of the comprehensive evaluation function f ₄ after the latest data in time series, and uses the time series predicted value and the limit value L to run The tire warning device according to claim 14 , wherein a time until the flat limit region is reached is calculated.

The tire temperature sensor (44)及beauty tire pressure Sensor (45) and the tire temperature sensor (44) and the tire side having a transmission means to transmit the detected signal (46) in the tire inner pressure sensor (45) A unit (42) , and a vehicle side unit (43) comprising a receiving means (48) for receiving a signal from the transmitting means (46) , the processing means (51) and the warning means (52). Item 20. The tire alarm device according to Item 2, 5, 11, 12, 13 , 14, or 15 .